The present invention relates to grout that has a cellular structure when it hardens, and can be used for structural (i.e., load bearing) purposes.
There have been numerous prior inventions of grouts and similar compositions, but none that are equivalent to the instant invention. Most grouts in the prior art are used for void filling applications, such as filling cracks in rocks, stabilizing soils, spaces around the outside of tunnel rings, filling voids in prestressing of cable ducts, radiation absorbing barriers, etc. By contrast, the grout of the present invention is suitable for use as a load bearing foundation material. This is possible due to the inclusion of road planings with flexible coatings in the grout. Road planings tend to be hard particles surrounded by a flexible coating such as bitumen, asphalt or tar. Each road planing forms a cell with the adjacent grout. The road planings act as arrestors to the growth of microcracks, which are endemic in any cement bound material during shrinkage and thermal movements, and allow the material to be semiflexible, in contrast to the brittleness of conventional concrete.
U.S. Pat. No. 3,788,081, issued on Jan. 29,1974, to Arthur Sarkisian and Charles F. Murphy, discloses a grouting composition which sets into a stable structure. The use of road planings, as in the instant invention, is not disclosed. Furthermore, there is no suggestion that the composition disclosed can be used for load bearing foundations, as can the instant invention.
U.S. Pat. No. 4,268,316, issued on May 19, 1981, to Milton H. Wills, Jr., discloses a masonry cement prepared by blending portland cement, kiln dust, and fly ash. The instant invention is distinguishable in that it includes road planings, and can be used for load bearing foundations.
U.S. Pat. No. 5,728,209, issued on Mar. 17, 1998, to Jeffry Bury, David F. Factor and Zvi Grauer, discloses a unitized cement admixture, again without any disclosure of the use of road planings.
U.S. Pat. No. 5,776,244, issued on Jul. 7, 1998, to Ernst H. Ahrens, discloses an ultrafine cementitious grout. The instant invention has a cellular structure that would be absent in an ultrafine grout.
U.S. Pat. No. 5,921,707, issued on Jul. 13, 1999, to Raymond Caulton Owen, discloses a method of filling an excavated opening in the surface of a highway, including the use of excavated spoil that is mixed with grout using mechanical agitation and a foaming agent. The instant invention does not require the use of mechanical agitation or a foaming agent, and it can be used for large massive foundations and many other purposes besides filling in excavated openings in highways. The instant invention is further distinguishable, in that it uses road that are ground off the surface of the road, rather than excavated spoil that has been dug out of the hole (or a similar hole) that it is being used to refill. As an old highway may have had numerous repairs, the excavated spoil of Owen is likely to be a mixture of flexibly-coated broken material, including surface material similar to road planings, and uncoated concrete and natural aggregates, which when mixed with grout, will give variable and unpredictable results. In contrast, the instant invention uses only the flexibly coated road planings, with results that can be accurately predicted.
U.S. Pat. No. 5,968,257, issued on Oct. 19, 1999, to Ernst H. Ahrens, discloses another ultrafine cementitious grout.
U.S. Pat. No. 6,046,374, issued on Apr. 4, 2000, to Patrick j. Stephen, discloses a cellular grout radiation barrier, which requires a xe2x80x9cradiation absorbing metal constituentxe2x80x9d and a foaming agent, which are not required by the instant invention.
British Patent. No. 1,080,004, complete specification published on Aug. 23, 1967, to Leslie Bulmer, discloses a new or improved concrete and a process for the manufacture thereof, with no disclosure of the use of road planings, as in the instant invention.
European Patent Application No. 0 496 263A3, filed on Jan. 15, 1992, inventors Hans Klausmann and Ralf Klausmann, discloses a method for reusing tar-based building materials, in which said materials are used to make building blocks.
European Patent Application No. 0 628 522A1, filed on May 19, 1994, inventor Wolfgang Zimmermann, discloses concrete for road surfaces, including grains larger than eight millimeters taken from recycled road surfaces.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
In the present invention, bitumen coated, asphalt coated, or tar coated road planings in a raw unprocessed state are added to a cement-pulverized fuel ash grout by either of two methods to produce a hardened structural cellular grout. The material is especially suitable for the construction of the sub-base to carriageways and footways and for trench reinstatements therein. Standard concrete mix admixtures can be used in the said grout to cater for specific site conditions.
Accordingly, it is a principal object of the invention to provide a new structural material.
It is another object of the invention to provide a use for recycled road planings.
It is a further object of the invention to provide a material suitable for load bearing foundations.
Still another object of the invention is to provide a material that can be used in the construction of highways, railway tracks, aircraft runways, car parks, ground slabs for buildings, etc.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.